Air pump



J. W. LAWHEAD.

AIR PUMP. APPUCM'ION FILED JAN-26, I920- 1,425,663, Patented Aug. 15, 1922.

3 SHEETFSHEET I.

P329. I f5 INVENTOR. Liam/w WIa/wheaaz ATTORNEYS.

l. LAWHEAD.

MR PUMP. Armcnmn FILED mmzs. 1920.

Patented Aug. 15, 1922.

3 SHEETS-SHEET 2.

I. LAWHEAD.

MR PUMP. APPHCAHON FILED mnzs. 1920.

Patented Aug. 15, 1922.

3 SHEETS-SHEET a.

III r WITNESSES:

um'ren sures PATENT ornce.

JAMES W. LAWHEAD, OF WILMINGTON, OHIO.

AIR PUMP.

1 425,663 Specification of Letters Patent. Patented A g 15, 1922 Application filed January 26, 1920. Serial 1105353941.

T ll h it may gitudinal section of an air pump in which Be it known that 1, JAMES \V. LAWHEAD. the improved valves have been applied; a citizen of the United States, residing at Fig. 2 is a plan view of the pump head of Wilmington, in the county of Clinton and the pump shown in Fig. 1, with part of the State of Ohio, have invented certain new cap plate cut away to show the relation of and useful Improvements in Air Pumps, of the valves relative to each other and the which the following is a specification, refer pump cylinder; and cure being had therein to the accompanying Figs. 3 and 4 are a plan view and a dedrawing. tall longitudinal sectional view, respec- This invention relates to air pump and tlvely, of a modified construction ot the has for its particular object to provide an pump head. air pump of improved construction which The invention may be embodied in any may be used either as an air compressor suitable construction. As here shown, the pump or as a vacuum pump, the construc air pump as a whole comprises a suitable tion and operation of the pump for the rebase casing 1, and pump cylinder casing 2; spective purposes being substantially the the casings being enlarged at their upper same, except as to the arrangement and opand lower ends, respectively, to form a crank cration of the valves. shaft bearing 3, for the crank shaft 4, and

An object of the invention is to provide having base flanges 5-6, whereby the upper an air pump of the type above indicated, base is properly seated and alined, relative provided with improved valves, the valves to the lower base, and secured thereto by as here shown being of the full gravity-acbolts 7 extending through the flanges 5-6. tion type in which all actuating mechanism As here shown the crank shaft bearings is eliminated, the operation of the valves are lined with sleeve bushings 8, and the being responsive entirely in one direction shaft is provided with a belt pulley 9, to the suction impulses of the pump piston whereby power may be ap lied to the pump and the resulting air pressure thereon, and from any suitable source.- Vithin the cylinin the opposite direction to combined gravder, the pump consists of the plunger 10, ity and air ressure movement. connected to the crank shaft in the usual It is an object of the invention to provide manner by a pitman 11, the construction valves that will retain their normal relashown being of a well known preferred tion under all ordinary conditions of operaform. tion, that are cheap to manufacture and The head of the pump cylinder comprises practically indestructible. a housing 12, cast integrally as here shown The type of pump here shown in which with the pump cylinder casing, being subthe invention in one ap roved form has been stantially larger in diameter than the cylin applied, is especially a aptable as a vacuum der casing, and having a eripheral flange pump for automatic milking apparatus for 13, formed at its upper en which serves as dairy use. In pumps of well known conthe base for the cylinder head plate 14 and struction of this general type in which ringcap plate 15, the parts being secured toplate valves are used, difliculty has been exgether by means of bolts 16. perienced with the valves due to the tWist- The housing 12 has an annular depression ing or warping of the rings, due to their or channel 17 formed therein, which is open light construction and relatively large size, to the end face of the cylinder casing, the and to the action of the heat thereon generchannel being normally closed by the cylinated by the air pump in operation. der head plate 14, which has a plurality of In the construction here shown singledepressions or pockets 18 formed therein, plate, full gravity-action valves are subcommunicatin between the pump cylinder stituted for the ring-plate valves, and the and the annu ar channel 17 and providing construction of the pump head and'base in clearance space and acting as a retainer for which the respective intake and discharge the valve plates 19. At its center the cylinvalves are located, is suitably modified to der head plate is provided with an outlet adapt the pump structure to the improved port 20, normally closed by a gravity valve valve construction. 21 whose upward movement is checked by In the accompanying drawinvs: the boss 23 of the cap plate 15; air Spaces Fig. 1 is a side elevation, partially in lon- 24, 25 and 26 being provided in the cap plate whereby air discharged through the port 20 may be delivered from thepump through an aperture 27 or suitable pipe extensions connected thereto.

e housing an intake port 28 which may be open any suitable connections with a vacuum tank or chamber when the pump is used in connection with a vacuum system.

At its base the c linder casing 2 may be provided as here shown with one or more exhaust valves, similar in construction to the intake valves in the housing 12, the exhaust valves consisting in the form shown of a valve housing 29, preferably cast integrally with the cylinder casing, and havin a discharge aperture 31 formed therein; t e aperture opening to the pump cylinder, and to the atmosphere at the top of the housing as shown by the o enin'g 34 and being normally closed at its d ischarge end b under a cap plate 30 minim zing and providing tainer for the valve plate 32 which normally closes the discharge end of the air passa 31.

Pom the foregoing detailed description the construction and operation of the imp-oved valves and the pump as a whole will readily understood, the operation being as follows: 7

When the pump is used as an air com ressor, the port 28 18 open to the atmospli Upon the down stroke of the piston a vacuum will be formed in the cylinder and air will rush in through port 28, the pressure raisin the valves 19, and the cylinder being heric pressure.

valves 19 to close under pressure and the air willbe forced through the air assages in the cylinder cap plate and may e delivered through any suitable connections therewith to a pressure tank.

en the pump is used in connection with a vacuum system, the port 28 is connected to the vacuum tank or chamber by suitable connections. Upon the down stroke of the iston air from the vacuum cylinder will ow to the pump cylinder until the pressure in e respective cylinders, when the piston is in the down stroke, is equalized or substantiall so, when the maximum vacuum state will effected in Upon the up stroke 21 will t a pump is used as an air compressor, except that no pipe extensions will be used in connection with the port 27 unless an air pressure system is used in combination with the vacuum system which may readily be one.

The exhaust port valves at the base of the be used with the pump either as pressure within the portion of the cylinder. On the up stroke the valves close, thus causing the ressure Within the lower portion of the cylinder to become less than atmospheric pressure, which tends to balance the action of the pis ton by minimizing of the friction thereon. While the exhaust valves are a desirable feature of the invention they are not essential to the successful operation oi the pump, either as an air compressor or in connection with a vacuum system e exhaust valves furthermore are effective to prevent oil, which is liberally supplied in the lower part or oil sump of the crank casing to automatically lubricate the mechanism, from being forced, undergreat her of the cylinder and thence cylinder into the pressure tank or open atmosphere. While the reduced pressure in the lower casing causes the oil to rise more rleadily in the casing on the up stroke of t e mm the the cylinder.

The modified form of the cylinder head shown in Figs. 3 and 4 is, in fact, the preferred form of construction. The gravity valves are lighter than the valve shown in Figs. 1 and 2 and respond more readily to the discharge pumping action of the cylin- Furthermore, the gravity members 35 of the valves are interchangeable with the corresponding parts 19 and valves and exhaust port, respectively. Thus, the construction of the pump as a whole is materially simplified and cheapened. It will be obvious from the illustration shown in Fig. 3 that the operation of i the modified valves is substantially the same as the operation of the gravity valve 21, the air passages 36 and 37 serving the same purpose as the corresponding passages 2425 and 26 in the construction shown in Fig. 1 l and the passages 38 leading to the valves 35 serving the same purpose as the direct opening into the cylinder of the valve passage 20.

From the foregoing detailed the construction, operation and results of operation of the improved pump will be readily understood by those experienced in this art.

Having thus fully description described my patent, I

Jll

32 of the intake ll what I claim as new and desire to secure by Letters Patent, is

1. In anair pump, the combination, with a cylinder having near one end an inlet port and a valve therefor opening inward, an outlet port and a valve therefor opening outward, and having near the other end an outlet passage and a valve therefor opening outward, of a piston operating within the cylinder between said ports, whereby on the suction stroke air is drawn into the cylinder, on the reverse stroke air is forced out of the cylinder and whereby any air that leaks between the cylinder and piston is discharged through said outlet port when the piston is making its suction stroke, thus relieving the piston of back pressure.

2. In an air pump, the combination, with a structure comprising at one end a cylinder and at the other a closed chamber, an inlet port for the cylinder end with a valve closing outward, an outlet port at said end with a valve closing inward, and an outlet port from the chamber-end with a valve closing inward, of a piston within the cylinder portion and a crank shaft within the chamber-portion, whereby on the suction stroke air is drawn into the cylinder and any air within the chamber is essentially discharged therefrom.

3. In an air pump, the combination, with a structure comprising a cylinder at one end and a closed chamber at the other, an air chamber having an inlet ort and communicating with one end of tlie cylinder, valves for said chamber opening inward, a plate having an outlet port with a valve opening outward, a assage from said chamber leading outwar and a valve therefor opening outward, of a piston in the cylinder and crank shaft in the chamber, whereby air is drawn into and discharged from the cylinder and whereby also any air that passes the piston and enters said chamber is essentially discharged.

4. In an air pump, the combination of a cylinder having a piston operable therein, a circumferential air chamber 17 having intake ports 28, and an annular air channel leadin into the cylinder near one end there-. of, an gravity-action valves normally closing communication between said circumferential air chamber and said annular air channel, and a closed casing at the other end of the cylinder, an exhaust port communicating with this end of the cylinder through said casing, and a gravity action valve for said port, whereby upon operation of the piston air will be takeniinto the cylinder on one side of the piston through said intake ports and annular air channel, and any air within the cylinder on the other side of the piston will be discharged to relieve the piston of back pressure.

In testimony whereof, I aflix m JAMES W. LAW HIfiAD.

si nature. 

